What makes it impossible to escape from a black hole?

Question

Can gravity get out of a black hole?

In the times of the big bang, why did the universe not collapse and form into a black hole instead?

These are questions set by my university that I am doing research on.

Please don't copy and paste lengthy text from WIKIPEDIA as that will be of no use.

If you do copy and paste anything, then could you put the website into the sources.

Thanks.

Answer 1

According to Einstein's general relativity (which, as far as we can tell, is correct), gravity is nothing more than the curvature of space due to the presence of mass.

Curvature is not something that has to 'escape' from a black hole.  Rather, the curvature is what makes it impossible for nearly anything inside the black hole's event horizon to escape.

Answer 2

Main question:

1. Black hole = escape speed greater than the speed of light; PLUS

2. Relativity = nothing (matter or information) can go faster than light.

Can gravity get out?

no

However (from our frame of reference), any object that falls into a black hole has its time flow slowed down as it falls deeper into the gravitational well, until it would appear "frozen" at the event horizon (the real object, of course, continues in, past the event horizon).

(This is from a  book around 1995, where the author proposed that black holes were better understood if we treated them like the 2-D event horizon -- the last thing which still belongs in our frame of reference), rather than a 3-D object with the inside constantly expanding inwardly (as in the classical models).

As far as we are concerned, the "gravity" information needed for space to acquire the correct curvature is still present at the event horizon.  Therefore gravity does not have to escape the black hole itself.

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Under Big Bang theory, we do not know what was going on at time = zero.

The best we can do is go back to the Planck Time (very close to zero).  At that time, the "temperature" was so high that every single point of the universe would have been a black hole (from energy content, not from mass).

It is even possible that gravity itself did not exist at that time (or before that time).

Using Hawking's idea, this infinity of zero-mass back holes would have evaporated instantly (probably triggering the expansion? -- be careful if you use this in your paper, I've never seen it in any paper).

It is possible that gravity was created at the same moment as the black holes disappeared.  The expansion rate could have been higher than the local (space AND time) speed of light, preventing re-collapse.  Or, if gravity was formed later (even if it was a tiny fraction of a second later), then separation was already too well established.

It is difficult to say when "mass" appeared.  I would vote for it to have appeared at the same time as gravity.  But I do not understand the Higgs field enough to venture beyond this guess.

Answer 3

gravity is not something that should escape, rather, it is the reason why nothing escapes a black hole. a black hole consists of gravity so strong that it can pull anything towards it, no matter what.

the reason for this is that a black hole is a very very small piece of matter with a great amount of density.

imagine our sun, for example, and then imagine all the matter in the sun compressed into an object even smaller than a pin head. that would be quite similar to a black hole.

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to answer your other question further, it has somewhat been proven that the universe will no collapse into a black hole in the future. the reason for this is similar to the concept of gravity above.

every object in our universe has gravity, no matter how weak it is. the thing is, if the universe had enough matter in it, then there would be enough gravity to pull it back on itself someday. but recent research has shown that the universe does not have enough matter to do this, so the universe will just keep expanding forever.

Answer 4

just a thort (wish footy season was here..then we get intelligent db8!)..Raymond's bit triggered a wee bit of sentient reasoning.. If the Universe is closed..ie if density (incl dark matter)>3*H^2/(8*pi*G) [I dervd this using escape vel^2=(H*R)^2=G*M/R..M=mass universe, H=Hubble const, R=rad universe)

Then universe contracts/collapses.Now watta u gonna do wit all them black holes??(as the universe shrinks)

I predict the coalescence of all their mass leading to a super-deflation (this is like playing the BB film backward!) due to released gravity. Do not think that experienced time would reverse but entropy wud decrease. When u get to the Planck size this 'universe rebounds'  (albeit with a small change in entropy)..so each time u get a bigger warmer universe! From complex thermodynamic calcs and present 3K background rad temp, we may have been through between 50-100 exp/contr already.

Answer 5

A black hole is a region of space in which the gravitational field is so powerful that nothing, not even light, can escape its pull after having fallen past its event horizon. The term "Black Hole" comes from the fact that, at a certain point, even electromagnetic radiation (e.g. visible light) is unable to break away from the attraction of these massive objects. This renders the hole's interior invisible or, rather, black like the appearance of space itself.

If light doesn't so human beings doesn't.

But the logic is, how can we know it if we haven't been there?

Let's try to think.

Answer 6

1.  What makes it impossible to escape from a black hole?

This is a common saying which attributes the inability of an object to exit a black hole to the gravity which exists at the event horizon.  The gravity at the event horizon of any black hole is 26,786 gees; which translates to an escape velocity of the speed of light.

However, escape velocity refers only to an unpowered projectile.  A powered projectile can escape the gravitational pull of an object at much less than escape velocity.  Case in point: any rocket launch from here on Earth.

Earth's escape velocity is 11.2 km/second which translates to a smidge over 25,000 mph.  I assure you that our rockets do not reach anywhere near that speed as they take off; yet they move rather steadily away from the Earth.

This leads us to the conclusion that if there were a really powerful ship, such as the Enterprise from Star Trek, it could have sufficient power to escape a black hole without even needing to exceed the speed of light.

HOWEVER, setting aside the fact of the fixed and finite value of gravitation at the event horizon of a black hole, it must be acknowledged that due to the effect of gravity on the flow of time in the vicinity of a black hole, it becomes impossible to escape from a black hole.

And vice versa; for exactly the same reason, contrary to common understanding even by Hawking, nothing ever enters a black hole.  The flow of time does not allow it to occur.

For it is commonly said and universally accepted that time at the event horizon has slowed to its minimum speed; that is, one increment of time exists at the event horizon for all the time that the universe exists.  During an increment of time (accepting that quantum theory applies to time), nothing happens.  Each increment of time is a given state.  In the following increment, there can be a change of state.

However, at the event horizon of a black hole, there is only one increment.  The event horizon of a black hole never changes its state.

And it is for this same reason that no one can know at this time what occurs beneath the surface of a black hole.  There is no math which now exists that allows us to divide by zero; for the next logical level of time flow below an event horizon would be zero increments.

So, in the end, given that a particle at the event horizon of a black hole were traveling at the speed of light away from the black hole, it would never experience a second increment of time in which to be not be at the event horizon but to be one Planck unit away.

This is also the reason to refute the operation of Hawking radiation.  Hawking proposes that a virtual particle materializes at the edge of an event horizon while its negative partner materializes at the event horizon.

If one completely ignores the effect of gravity on the flow of time in this instance, one can see how the negative virtual particle is pulled away from its positive partner and they both become real.  The negative one reduces the mass of the black hole while the positive one moves away from the black hole.

However, we MUST acknowledge that time is highly affected in this same instance.  If the positive virtual particle came into existence, it was preceded by a state of it not existing.  The first frame of time had no particle in it.  The second frame of time had a particle in it.

In order for the particle to wander away (as it is so often described), at least one more frame of time must occur.  However, at the distance in question, another frame of time does not ever occur.

It is for the reason that gravity so greatly affects the flow of time that nothing can escape a black hole and has hardly anything to do with sheer escape velocity or powered flight.

2.  Can gravity get out of a black hole?

Gravity "escapes" a black hole because gravity is a quality of the fabric of space-time affected by the presence of mass and is not a thing in the conventional sense; even if that conventional sense includes massless photons.

3.  At the time of the Big Bang, why did not the universe not collapse and form into a black hole?

The Primordal Particle consisted of not only of all matter but of all energy also.  A black hole consists only of matter; thus its over-riding property is gravity.  It was the energy which caused the expansion of the universe from its initial small state.

However, gravity continues to do its work and regardless of the supposed action of dark energy, I feel that the universe will reach a state of all matter and all energy becoming equally distributed in the manner of heat death.  Time will stop for there will be no changes of state as gravity holds the entirety of the universe in a perfect balance.  And in such a state, the most natural state of all, the universe can exist timelessly.  

And one day, an influence from outside the universe can start the universe up again.  There will commence the Universal Contraction, during which stars and galaxies form, life comes to exist, and so forth.  Until it all ends in the Big Crunch... which immediately leads to the Big Bang.

So, technically, in our universe as we know it now, time is running backward...

Answer 7

Apparently, gravity and magnetism can reach out of a black hole.  Gravity makes sense, if you use Einstein's stretching of the fabric of space analogy.   It make alot less sense if there are virtual gravitons that make gravity work.  I've wondered about magnetism, though.  The field lines don't actually move.  That is, nothing moves the length of a field line.  So maybe magnetism works like gravity, only it's a different field.

One of the theories about the big bang suggests that a small amount of mass appeared out of the quantum foam.  There is no true vacuum, instead, pairs of particles appear and disappear constantly.  Perhaps an unlikely amount appeared at once, and stretched the local fabric of space.  This stretching caused more matter and energy to appear, which stretched the fabric more... and the result was the Universe.  It's not the only idea, and it hasn't been proven.  I expect that we won't know before we get a grand unified physics theory that combines quantum mechanics and general relativity.  Maybe not even then.  Anyway, this idea and others avoid the singularity black hole at the beginning.

Answer 8

Gravity is what makes it impossible to escape a black hole, and gravity is EVERYWHERE. You can't stop gravity from reaching you. Otherwise we'd be building anti-gravity spaceships and such. Gravity can affect everything around the black hole, but it's not affected by anything else apart from the black hole's mass. And the bigger the mass, the stronger the gravity!

"In the times of the big bang, why did the universe not collapse and form into a black hole instead?" - the forces that caused its expansion were stronger than the force of gravity.

Answer 9

Simpley stated when a massive star implodes and creates a black hole its mass is so massive that the black hole produced won't let matter escape even light cannot escape it's gravitational pull once matter reaches the event horizon. (The point of no return) Gravity itself doesn't escape because gravity is what is causing this phenomenom. Gravity exerts it's force on EVERYTHING in the universe. It is all encompassing and all matter in exsistence is governed by gravity. There is no escaping it. After a black hole swallows something there has to be some conversion of the matter. As for as the concensus small amounts of radiation are ejected into space out the other side I think.